[workflows] Use shallow git clone in workflows (#8166)

Some our github workflows fetch the entire commit history,
allegedly to make bloat reports work, but after examining
the bloat check script it appears that the requirement may
be no longer valid. The bloat check script used to be run
as part of the PR workflows, but now there's a separate
workflow for the bloat report. Let's try if we can safely
switch to the shallow cloning.

.github/workflows/examples-efr32.yaml

@@ -42,9 +42,7 @@ jobs:
         steps:
             - name: Checkout
               uses: actions/checkout@v2
-              # Fetch depth 0 to get all history and be able to check mergepoint for bloat report
               with:
-                  fetch-depth: 0
                   submodules: true
 #             - name: Initialize CodeQL
 #               uses: github/codeql-action/init@v1

.github/workflows/examples-esp32.yaml

@@ -43,9 +43,7 @@ jobs:
         steps:
             - name: Checkout
               uses: actions/checkout@v2
-              # Fetch depth 0 to get all history and be able to check mergepoint for bloat report
               with:
-                  fetch-depth: 0
                   submodules: true
 #             - name: Initialize CodeQL
 #               uses: github/codeql-action/init@v1

.github/workflows/examples-k32w.yaml

@@ -41,9 +41,7 @@ jobs:
         steps:
             - name: Checkout
               uses: actions/checkout@v2
-              # Fetch depth 0 to get all history and be able to check mergepoint for bloat report
               with:
-                  fetch-depth: 0
                   submodules: true
 #            - name: Initialize CodeQL
 #              uses: github/codeql-action/init@v1

.github/workflows/examples-linux-standalone.yaml

@@ -42,9 +42,7 @@ jobs:
         steps:
             - name: Checkout
               uses: actions/checkout@v2
-              # Fetch depth 0 to get all history and be able to check mergepoint for bloat report
               with:
-                  fetch-depth: 0
                   submodules: true
 #             - name: Initialize CodeQL
 #               uses: github/codeql-action/init@v1

.github/workflows/examples-mbed.yaml

@@ -47,9 +47,7 @@ jobs:
         steps:
             - name: Checkout
               uses: actions/checkout@v2
-              # Fetch depth 0 to get all history and be able to check mergepoint for bloat report
               with:
-                  fetch-depth: 0
                   submodules: true
 
             - name: Build example

.github/workflows/examples-nrfconnect.yaml

@@ -42,9 +42,7 @@ jobs:
         steps:
             - name: Checkout
               uses: actions/checkout@v2
-              # Fetch depth 0 to get all history and be able to check mergepoint for bloat report
               with:
-                  fetch-depth: 0
                   submodules: true
             - name: Bootstrap
               timeout-minutes: 25

.github/workflows/examples-qpg.yaml

@@ -41,9 +41,7 @@ jobs:
         steps:
             - name: Checkout
               uses: actions/checkout@v2
-              # Fetch depth 0 to get all history and be able to check mergepoint for bloat report
               with:
-                  fetch-depth: 0
                   submodules: true
 #             - name: Initialize CodeQL
 #               uses: github/codeql-action/init@v1