pin rustc to 1.44 (#66)

Summary:
This fixes build errors on GitHub.

Pull Request resolved: #66

Reviewed By: jsgf

Differential Revision: D24254833

Pulled By: lukaspiatkowski

fbshipit-source-id: 85cd791f0ef86cc791885fe5cfcbee3a9b88af39

Author: lukaspiatkowski

.github/workflows/eden_scm_lib_edenapi_tools_linux.yml

@@ -18,7 +18,7 @@ jobs:
     - name: Install Rust Stable
       uses: actions-rs/toolchain@v1
       with:
-        toolchain: stable
+        toolchain: 1.44.0
         default: true
         profile: minimal
     - name: Install system deps

.github/workflows/eden_scm_lib_edenapi_tools_mac.yml

@@ -16,7 +16,7 @@ jobs:
     - name: Install Rust Stable
       uses: actions-rs/toolchain@v1
       with:
-        toolchain: stable
+        toolchain: 1.44.0
         default: true
         profile: minimal
     - name: Install system deps

.github/workflows/edenscm_linux.yml

@@ -18,7 +18,7 @@ jobs:
     - name: Install Rust Stable
       uses: actions-rs/toolchain@v1
       with:
-        toolchain: stable
+        toolchain: 1.44.0
         default: true
         profile: minimal
     - name: Install Python 2.7

.github/workflows/edenscm_mac.yml

@@ -16,7 +16,7 @@ jobs:
     - name: Install Rust Stable
       uses: actions-rs/toolchain@v1
       with:
-        toolchain: stable
+        toolchain: 1.44.0
         default: true
         profile: minimal
     - name: Install Python 2.7