Update default dfx version

Author: berestovskyy

.github/workflows/provision-darwin.sh

@@ -18,7 +18,7 @@ rm node.pkg
 
 # Install DFINITY SDK.
 curl --location --output install-dfx.sh "https://internetcomputer.org/install.sh"
-DFX_VERSION=${DFX_VERSION:=0.12.0} bash install-dfx.sh < <(yes Y)
+DFX_VERSION=${DFX_VERSION:=0.15.2} bash install-dfx.sh < <(yes Y)
 rm install-dfx.sh
 dfx cache install
 

.github/workflows/provision-linux.sh

@@ -13,7 +13,7 @@ rm install-node.sh
 
 # Install DFINITY SDK.
 wget --output-document install-dfx.sh "https://internetcomputer.org/install.sh"
-DFX_VERSION=${DFX_VERSION:=0.12.0} bash install-dfx.sh < <(yes Y)
+DFX_VERSION=${DFX_VERSION:=0.15.2} bash install-dfx.sh < <(yes Y)
 rm install-dfx.sh
 dfx cache install
 

.github/workflows/rust-canister-info-example.yml

@@ -19,7 +19,7 @@ jobs:
     steps:
       - uses: actions/checkout@v1
       - name: Provision Darwin
-        run: DFX_VERSION="0.14.2" bash .github/workflows/provision-darwin.sh
+        run: bash .github/workflows/provision-darwin.sh
       - name: Rust Canister info Darwin
         run: |
           dfx start --background
@@ -31,7 +31,7 @@ jobs:
     steps:
       - uses: actions/checkout@v1
       - name: Provision Linux
-        run: DFX_VERSION="0.14.2" bash .github/workflows/provision-linux.sh
+        run: bash .github/workflows/provision-linux.sh
       - name: Rust Canister info Linux
         run: |
           dfx start --background

.github/workflows/rust-hello-example.yml

@@ -18,8 +18,6 @@ jobs:
     steps:
       - uses: actions/checkout@v1
       - name: Provision Darwin
-        env:
-          DFX_VERSION: 0.13.1
         run: bash .github/workflows/provision-darwin.sh
       - name: Rust Hello Darwin
         run: |
@@ -32,8 +30,6 @@ jobs:
     steps:
       - uses: actions/checkout@v1
       - name: Provision Linux
-        env:
-          DFX_VERSION: 0.13.1
         run: bash .github/workflows/provision-linux.sh
       - name: Rust Hello Linux
         run: |

.github/workflows/rust-periodic_tasks-example.yaml

@@ -18,8 +18,6 @@ jobs:
     steps:
       - uses: actions/checkout@v1
       - name: Provision Darwin
-        env:
-          DFX_VERSION: 0.13.1
         run: bash .github/workflows/provision-darwin.sh
       - name: Rust Periodic Tasks Darwin
         run: |
@@ -32,8 +30,6 @@ jobs:
     steps:
       - uses: actions/checkout@v1
       - name: Provision Linux
-        env:
-          DFX_VERSION: 0.13.1
         run: bash .github/workflows/provision-linux.sh
       - name: Rust Periodic Tasks Linux
         run: |